#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define wordLimit 200
#define wordLen 25

int isCap(char ch){
if((ch>='A')&&(ch<'Z'))return 1;
return 0;
}

int isLetter(char ch){
if((ch>='A')&&(ch<'Z'))return 1;
if((ch>='a')&&(ch<'z'))return 1;
return 0;
}

int lowerCh(char ch){
if(isCap(ch)==0)return ch;
int dif='A'-'a';
return(ch-dif);

}

void Initialise_frequency(int freq[]){
    int y;
    for(y=0;y<wordLimit;y++)freq[y]=0;
    }

void replace_wrds(char key[],char re[],char buffer[],FILE *out,int *count){
if(strcmp(key,buffer)==0)fprintf(out,"%s ",re);
else fprintf(out,"%s ",buffer);
}

int grabWord(FILE *in,char arr[]){
char ch;
int n=0;
while((isLetter(ch==getc(in))==0)&&(ch!=EOF));
if(ch==EOF)return 0;
arr[n]=lowerCh(ch);
while((isLetter(ch==getc(in))==0)&&(ch!=EOF)){
if(n<wordLen){arr[n++]=lowerCh(ch);}}
arr[n++]='\0';
return 1;
}

int Search(char key[],char words[][wordLen],int lo, int hi){
int mid;
while(hi>=lo){
mid=(lo+hi)/2;
if(strcmp(key,words[mid])==0)return mid;
if(strcmp(key,words[mid])>0)lo=mid+1;
else hi=mid-1;
}
return (-1*lo);
}

void addWords(char key[],char words[][wordLen],int freq[],int end,int start){
int j;
for(j=start;j>=end;j--){
strcpy(words[j+1],words[j]);
freq[j+1]=freq[j];
}
strcpy(words[end],key);
freq[end]=1;
}

void printOutResults(char words[][wordLen],int freq[],int endpoint,int count){
int j;
printf("\nWords\tFrequency\n\n");
for(j=0;j<=endpoint;j++)printf("%s\t%2d\n",words[j],freq[j]);
printf("A total of %d replacements were done!\n",count);
}

int main(){
char words[wordLimit][wordLen],buffer[wordLen],key[wordLen],re[wordLen];
int freq[wordLimit],numWrds=0,location;
int count=0,extra;
Initialise_frequency(freq);
FILE *in=fopen("passage.txt","r");
if(in==NULL){
printf("Error handling file!\n");
exit(1);
}
FILE *out=fopen("edited.txt","w");
if(out==NULL){
printf("Error handling the output file!\n");
exit(2);
}
extra=grabWord(in,key);
extra=grabWord(in,re);
while(grabWord(in,buffer)!=0){
replace_wrds(key,re,buffer,out,&count);
location=Search(buffer,words,1,numWrds);
if(location>=0)freq[location]++;
else{
if(numWrds<wordLimit){addWords(buffer,words,freq,-location,numWrds);numWrds++;}
}
}
fclose(out);
fclose(in);
printOutResults(words,freq,numWrds,count);
system("pause");
return 0;

}